Ultrasound is a ubiquitous technology capable of obtaining images, assessing functions, measuring hemodynamics, characterizing tissues, visualizing fluid flows, etc. One of the major attributes of ultrasound is its safety, adaptability, low cost, and high spatial and temporal resolution. The ultrasound energy utilized has been proven to be safe and currently used in most medical environments, such as fetus, intravascular, indwelling, intracavitary, etc.
Current ultrasound transducer devices are typically comprised of a piezoelectric transducer, which sends and receives ultrasound, from which transformed ultrasound information is processed into real time images or other meaningful presentations, such as Doppler shift, tissue characterization, visualization of blood flow, etc. Over the years, ultrasound transducers have been incorporated into smaller devices, such as catheters disclosed in U.S. Pat. Nos. 5,325,860; 5,345,940; 5,713,363; 5,704,361, etc., by Seward et al., assigned to Mayo Foundation for Medical Education and Research, the common assignee of the present invention. In general, these catheters are thin tubes, which can be pushed into and manipulated within vessels or cavities. A transducer is disposed proximate a distal end of the catheter and generates underfluid images in the field of view. The shaft of these catheters is as large or larger than the transducer. The catheter is specifically designed to be manipulated by push/pull, using the torque of the catheter shaft and indwelling cables for tip articulation. Thus, the catheter is navigated through or within blood vessels, body cavities, and orifices, etc., and ultrasound functions as a visual substitute for visualizing the underfluid structure within the blood vessels, body cavities, and orifices, etc.
The current disclosure deals with small transducer technology without the accoutrements or intended use of a catheter. For example, the small transducer technology disclosed below may not have a catheter shaft, which is conventionally used to manipulate the ultrasound transducer within vessels or cavities to an intended location. Such a semi-rigid shaft might limit the motion or application of such an unencumbered small ultrasound transducer made in accordance with currently disclosed technology. Such unencumbered small transducers are distinct from the previously disclosed technology. The unencumbered small transducer as disclosed herein might not be navigated through vessels and cavities using a semi-rigid shaft but might be physically placed on or within the intended viewing field. The small transducer might be physically attached to a holding device, or a finger, or secured within or adjacent the intended viewing field by a suture. Such a small transducer might aid and foster the use of ultrasound visualization for the surface of a structure such as the liver, the heart, a blood vessel, the brain, etc. when the transducer is placed on or adjacent to such a structure. Alternatively, when attached to the finger, such a transducer might allow imaging from within a cavity, such as the vagina, the rectum, the mouth, the abdominal cavity, etc. Further, when attached to a tool, such a transducer might allow ultrasound visualization from within a space which is at that moment visually inaccessible, such as at the point of incision of the cutting edge of a blade, along a cannula during an insertion, or of the area around an implanted device such as an artificial organ, etc.
The present disclosure deals with small transducers which enable the use of ultrasound to empower visualization from environments normally inaccessible to the naked eye. In the field of medicine and related endeavors light visualization may be impossible or significantly encumbered. The present disclosure deals specifically with a stand alone small ultrasound transducer technology devoid of those features typically found in known catheter or other hand-held device. Specifically, the present disclosure relates to transducer embodiments where there are no attachments to the transducer other than those directly intended to foster the placement and/or securing of the ultrasound transducer at the desired location.
Characteristics of the surgical environment include need for sterility, small adaptable tools which can be incorporated into a surgical probe or finger, navigate very small spaces, unencumbered by cables, and do not cause injury to delicate tissues. Accordingly, it is desirable as described within the present disclosure to have even smaller or miniaturized ultrasound transducers to meet the characteristics or needs of the surgical or other medical environments. Ultrasound transducers disclosed herein would include small hand-held ultrasound transducers, small enough to be easily accommodated within the confines of the surgical field (e.g. closed and/or confined spaces, adjacent to small or delicate structures, etc.)